SIST EN 62369-1:2009

SLOVENSKI STANDARD
01-september-2009
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Evaluation of human exposure to electromagnetic fields from short range devices (SRDs)
in various applications over the frequency range 0 GHz to 300 GHz -- Part 1: Fields
produced by devices used for electronic article surveillance, radio frequency identification
and similar systems
Ermittlung der Exposition von Personen gegenüber elektromagnetischen Feldern im
Frequenzbereich 0 Hz bis 300 GHz durch Geräte mit kurzer Reichweite für verschiedene
Anwendungen -- Teil 1: Felder, die durch Geräte erzeugt werden, die zur elektronischen
Artikelüberwachung, Hochfrequenz-Identifizierung und für ähnliche Anwendungen
verwendet werden
Evaluation de l'exposition humaine aux champs électromagnétiques produits par les
dispositifs radio à courte portée dans la plage de fréquence 0 GHz à 300 GHz -- Partie 1:
Champs produits par les dispositifs utilisés pour la surveillance électronique des objets,
l'identification par radiofréquence et les systèmes similaires
Ta slovenski standard je istoveten z: EN 62369-1:2009
ICS:
13.280 Varstvo pred sevanjem Radiation protection
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 62369-1
NORME EUROPÉENNE
March 2009
EUROPÄISCHE NORM
ICS 33.050 Supersedes EN 50357:2001

English version
Evaluation of human exposure to electromagnetic fields
from short range devices (SRDs) in various applications
over the frequency range 0 GHz to 300 GHz -
Part 1: Fields produced by devices used for electronic article surveillance,
radio frequency identification and similar systems
(IEC 62369-1:2008)
Evaluation de l'exposition humaine  Ermittlung der Exposition
aux champs électromagnétiques von Personen gegenüber
produits par les dispositifs radio elektromagnetischen Feldern
à courte portée dans la plage im Frequenzbereich 0 GHz bis 300 GHz
de fréquence 0 GHz à 300 GHz - durch Geräte mit kurzer Reichweite
Partie 1: Champs produits für verschiedene Anwendungen -
par les dispositifs utilisés pour Teil 1: Felder, die durch Geräte erzeugt
la surveillance électronique des objets, werden, die zur elektronischen
l'identification par radiofréquence Artikelüberwachung,
et les systèmes similaires Hochfrequenz-Identifizierung und für
(CEI 62369-1:2008) ähnliche Anwendungen verwendet werden
(IEC 62369-1:2008)
This European Standard was approved by CENELEC on 2009-03-01. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and notified
to the Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: avenue Marnix 17, B - 1000 Brussels

© 2009 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 62369-1:2009 E
Foreword
The text of the International Standard IEC 62369-1:2008, prepared by IEC TC 106, Methods for the
assessment of electric, magnetic and electromagnetic fields associated with human exposure, was
submitted to the Unique Acceptance Procedure and was approved by CENELEC as EN 62369-1 on
2009-03-01 without any modification.
This European Standard supersedes EN 50357:2001.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2010-03-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2012-03-01
__________
Endorsement notice
The text of the International Standard IEC 62369-1:2008 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:
IEC 61566 NOTE  Harmonized as EN 61566:1997 (not modified).
IEC 62209-1 NOTE  Harmonized as EN 62209-1:2006 (not modified).
IEC 62311 NOTE  Harmonized as EN 62311:2008 (modified).
ISO/IEC 17025 NOTE  Harmonized as EN ISO/IEC 17025:2005 (not modified).
__________
IEC 62369-1
Edition 1.0 2008-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Evaluation of human exposure to electromagnetic fields from short range
devices (SRDs) in various applications over the frequency range 0 GHz
to 300 GHz –
Part 1: Fields produced by devices used for electronic article surveillance,
radio frequency identification and similar systems

Evaluation de l'exposition humaine aux champs électromagnétiques produits
par les dispositifs radio à courte portée dans la plage de fréquence 0 GHz
à 300 GHz –
Partie 1: Champs produits par les dispositifs utilisés pour la surveillance
électronique des objets, l'identification par radiofréquence et les systèmes
similaires
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
XB
CODE PRIX
ICS 33.050 ISBN 2-8318-9969-9
– 2 – 62369-1 © IEC:2008
CONTENTS
FOREWORD.5
INTRODUCTION.7
1 Scope.8
2 Normative references .9
3 Terms, definitions, and abbreviations .9
3.1 Quantities.9
3.2 Constants.9
3.3 Terms and definitions .10
4 Measurements and calculations for equipment evaluation .15
4.1 Introduction .15
4.2 Evaluation against reference values .16
4.2.1 General .16
4.2.2 Direct measurement for comparison against reference values .16
4.2.3 Spatial measurements for comparison against reference values .17
4.2.4 Modelling and analysis including field non-uniformity.17
4.3 Specific absorption rate (SAR) measurements.24
4.3.1 General .24
4.3.2 Internal electric field strength measurements.24
4.3.3 Internal temperature measurements .25
4.3.4 Calorimetric measurements of heat transfer .26
4.3.5 Phantom models and fluid .26
4.4 Numerical evaluations for comparison against basic restrictions.26
4.4.1 General .26
4.4.2 Evaluations using homogeneous models .26
4.4.3 Special case of inductive near-field exposure 100 kHz to 50 MHz.28
4.4.4 Frequencies > 50 MHz.29
4.4.5 Localised SAR (100 kHz to 10 GHz) .29
4.5 Evaluations using non-homogeneous models for comparison against basic
restrictions .30
4.5.1 General .30
4.5.2 Anatomical body models.30
4.5.3 Calculation/modelling method.31
4.5.4 Position of the body in relation to the unit under evaluation .31
4.6 Measurement of limb and touch currents .31
5 Measurements for field monitoring.32
5.1 General .32
5.2 Field measurements .32
5.2.1 Measurement where persons spend significant periods of time.32
5.2.2 Detailed measurements for non-transitory exposure .32
5.3 Additional evaluation .32
6 Exposure from sources with multiple frequencies or complex waveforms.33
7 Exposure from multiple sources.33
8 Uncertainty.34
8.1 General .34
8.2 Evaluating uncertainties .34
8.2.1 Individual uncertainties.34

62369-1 © IEC:2008 – 3 –
8.2.2 Combining uncertainties .35
8.3 Examples of typical uncertainty components .35
8.3.1 Measurement.35
8.3.2 Numerical calculation .35
8.4 Overall uncertainties .35
9 Evaluation report .35
Annex A (informative) Characteristics of equipment .37
Annex B (informative) Information for numerical modelling.47
Annex C (informative) A simplified method for summation of multiple sources .67
Annex D (informative) Uncertainty .70
Bibliography.71
Figure 1 – General torso grid .19
Figure 2 – General head grid .19
Figure 3 – Single floor standing antenna.20
Figure 4 – Dual floor standing antenna .20
Figure 5 – Single floor antenna .21
Figure 6 – Single ceiling antenna.21
Figure 7 – Combined floor and ceiling antennas.22
Figure 8 – “Walk-through” loop antenna .22
Figure 9 – Counter or desk mounted antenna .23
Figure 10 – Vertical, wall or frame mounted antenna.23
Figure 11 – Hand-held antenna.24
Figure 12 – Disk model .28
Figure 13 – Cubic model .28
Figure 14 – Spheroid model .28
Figure A.1 – Example of exit mounted equipment showing detection range.40
Figure A.2 – Example of aisle mounted equipment.40
Figure A.3 – Inductive coupling.42
Figure A.4 – Electromagnetic coupling .42
Figure A.5 – Capacitive coupling.42
Figure A.6 – Overview of an RFID system.44
Figure B.1 – Current induced in a loop.47
Figure B.2 – Disk model.51
Figure B.3 – Disk model used for validations .51
Figure B.4 – Cubic model.52
Figure B.5 – Cubic model example showing current induced in 3 dimensions.53
Figure B.6 – Prolate spheroid .54
Figure B.7 – Helmholtz coils and prolate spheroid.55
Figure B.8 – 60 cm by 30 cm prolate spheroid results (magnetic field) .56
Figure B.9 – 60 cm by 30 cm prolate spheroid results (induced current density) .56
Figure B.10 – 120 cm by 60 cm prolate spheroid results (magnetic field) .57
Figure B.11 – 120 cm by 60 cm prolate spheroid results (induced current density).57
Figure B.12 – 160 cm by 80 cm prolate spheroid results (magnetic field) .58

– 4 – 62369-1 © IEC:2008
Figure B.13 – 160 cm by 80 cm prolate spheroid results (induced current density).58
Figure B.14 – Homogeneous human shape body model.60
Figure B.15 – Homogeneous human shape (induced current) .60
Figure B.16 – Homogeneous hand model.61
Figure B.17 – Approximate conductivities for LF homogeneous body modelling .66
Table 1 – Dimensions and distances for Figures 1 to 11 .18
Table 2 – Dimensions and distances for simplified body shapes .27
Table 3 – Maximum total evaluation uncertainties .35
Table A.1 – Frequency ranges and typical system characteristics .43
Table A.2 – Example frequency bands and their applications.43
Table B.1 – Disk model dimensions for Figure B.2 .51
Table B.2 – Cubic disk model dimensions for Figure B.4.52
Table B.3 – Prolate spheroid dimensions for Figure B.6.54
Table B.4 – Summary of results .59
Table B.5 – Examples of anatomical models .62
Table B.6 – Conductivity of tissue types.64
Table B.7 – Relative permittivity of tissue types .65

62369-1 © IEC:2008 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
EVALUATION OF HUMAN EXPOSURE TO ELECTROMAGNETIC FIELDS
FROM SHORT RANGE DEVICES (SRDS) IN VARIOUS APPLICATIONS
OVER THE FREQUENCY RANGE 0 GHz to 300 GHz –
Part 1: Fields produced by devices used for electronic article
surveillance, radio frequency identification and similar systems
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
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with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
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8) Attention is drawn to the normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62369-1 has been prepared by IEC technical committee 106:
Methods for the assessment of electric, magnetic and electromagnetic fields associated with
human exposure.
The text of this standard is based on the following documents:
FDIS Report on voting
106/156/FDIS 106/159/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.

– 6 – 62369-1 © IEC:2008
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The list of all parts of IEC 62369 series, published under the title Evaluation of human
exposure to electromagnetic fields from short range devices (SRDs) in various applications
over the frequency range 0 GHz to 300 GHz, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
62369-1 © IEC:2008 – 7 –
INTRODUCTION
Electromagnetic fields interact with the human body and other biological systems through a
number of physical mechanisms. The main mechanisms of interaction are based on nervous
system effects and heating. These effects are dependent on frequency and are defined by
biologically relevant quantities. Based on these scientifically established health effects, there
are international, regional and sometimes national exposure requirements. These are set as
basic restrictions on quantities, which are not necessarily directly measurable, and contain
high safety factors to ensure a high level of protection. These quantities may be determined
either by calculation for each case, or by measuring a reference value that has a pre-derived
relationship to them, usually under worst-case, far-field conditions. Respect of the reference
value will ensure respect of the relevant basic restriction, except in some specific near field
situations which would normally be identified or highlighted within the applicable exposure
guidelines. If the measured quantity exceeds the reference value, it does not necessarily
follow that the basic restriction is also exceeded. Under those circumstances, more detailed
evaluation techniques will be necessary which are specific to that type of equipment and
exposure.
This document is part of a multi-part standard covering the evaluation of human exposure to
electromagnetic fields from short range devices (SRDs) in various applications over the
frequency range from 0 GHz to 300 GHz.

– 8 – 62369-1 © IEC:2008
EVALUATION OF HUMAN EXPOSURE TO ELECTROMAGNETIC FIELDS
FROM SHORT RANGE DEVICES (SRDS) IN VARIOUS APPLICATIONS
OVER THE FREQUENCY RANGE 0 GHz to 300 GHz –
Part 1: Fields produced by devices used for electronic article
surveillance, radio frequency identification and similar systems
1 Scope
This part of IEC 62369 presents procedures for the evaluation of human exposure to
electromagnetic fields (EMFs) from devices used in electronic article surveillance (EAS), radio
frequency identification (RFID) and similar applications. It adopts a staged approach to
facilitate compliance assessment. The first stage (Stage 1) is a simple measurement against
the appropriate derived reference values. Stage 2 is a more complex series of measurements
or calculations, coupled with analysis techniques. Stage 3 requires detailed modelling and
analysis for comparison with the basic restrictions. When assessing any device, the most
appropriate method for the exposure situation may be used.
At the time of writing this International Standard, electronic article surveillance, radio
frequency identification and similar systems do not normally operate at frequencies below
1 Hz or above 10 GHz. EMF exposure guidelines and standards can cover a wider range of
frequencies, so clarification on the required range is included as part of the evaluation
procedures.
The devices covered by this document normally have non-uniform field patterns. Often these
devices have a very rapid reduction of field strength with distance and operate under near-
field conditions where the relationship between electric and magnetic fields is not constant.
This, together with typical exposure conditions for different device types, is detailed in
Annex A.
Annex B contains comprehensive information to assist with numerical modelling of the
exposure situation. It includes both homogeneous and anatomical models as well as the
electrical properties of tissue.
This International Standard does not include limits. Limits can be obtained from separately
published human exposure guidelines. Different guidelines and limit values may apply in
different regions. Linked into the guidelines are usually methods for summation across wider
frequency ranges and for multiple exposure sources. These shall be used. A simplified
method for summation of multiple sources is contained in Annex C. This has to be used with
care as it is simplistic and will overestimate the exposure; however it is useful as a guide,
when the results of different evaluations are in different units of measure which are not
compatible.
Different countries and regions have different guidelines for handling the uncertainties from
the evaluation. Annex D provides information on the two most common methods.
A bibliography at the end of this standard provides general information as well as useful l
1)
information for the measurement of electromagnetic fields. See [1],[2],[3],[4],[5],[6] .
Similar national or international standards may be used as an alternative.
———————
1)
Figures between brackets refer to the bibliography.

62369-1 © IEC:2008 – 9 –
2 Normative references
None.
3 Terms, definitions, and abbreviations
The internationally accepted SI units are used throughout this document.
3.1 Quantities
Quantity Symbol Unit Dimension
Magnetic flux density B tesla  (Vs/m) T
–2
Electric flux density D coulomb per square metre Cm
–1
Electric field strength E volt per metre Vm
Frequency fhertz Hz
–1
Magnetic field strength H ampere per metre Am
–2
Current density J ampere per square metre Am
–2
Power density S watt per square metre Wm
–1
Specific absorption rate SAR watt per kilogram Wkg
Temperature Tkelvin K
–1
Permittivity farad per metre Fm
ε
Wavelength metre m
λ
–1
Permeability henry per metre Hm
μ
–3
Mass density kilogram per cubic metre kgm
ρ
–1
Electric conductivity siemens per metre Sm
σ
3.2 Constants
Physical constant Symbol Magnitude
8 –1
Velocity of light in free space c 2,998 × 10 ms
–12 –1
Permittivity of free space
ε 8,854 × 10 Fm
–7 –1
Permeability of free space μ 4π × 10 Hm
Impedance of free space Z 120π (or 377) Ω
– 10 – 62369-1 © IEC:2008
3.3 Terms and definitions
3.3.1
antenna
antennas are conductive elements that radiate, and/or receive energy in the radio frequency
spectrum
3.3.2
average (temporal) absorbed power
P
avg
time – averaged rate of energy transfer defined by:
t2
P = P(t)dt
avg
³
t − t
2 1
t1
where t and t are the start and stop time of the exposure (the period t – t is the exposure
1 2 2 1
duration)
3.3.3
averaging time
t
avg
appropriate time over which exposure is averaged for purposes of determining compliance
3.3.4
bandwidth
range or band of frequencies in the electromagnetic spectrum within which a system is
capable of receiving and transmitting
3.3.5
basic restrictions (or basic limits)
values for human exposure to time-varying electric, magnetic, and electromagnetic fields that
are based on levels for which there are established health effects, with a high level of safety
included. These values may be defined in terms of induced current density, in-situ electric
field, specific absorption rate or similar dosimetric quantity
3.3.6
carrier
frequency used to carry data by appropriate modulation of the carrier waveform
3.3.7
conductivity
σ
ratio of the conduction–current density in a medium to the electric field strength in the medium
J = σE
3.3.8
current density
J
electromagnetic field-induced current per unit area inside the body
3.3.9
deactivator
device which changes transponders so that they no longer respond

62369-1 © IEC:2008 – 11 –
3.3.10
dielectric constant
ε
See permittivity.
3.3.11
electric field strength
E
magnitude of a field vector at a point that represents the force (F) on an infinitely small charge
(q) divided by the charge
F
E =
q
3.3.12
electric flux density
D
magnitude of a field vector that is equal to the electric field strength (E) multiplied by the
permittivity (ε)
D = εE
3.3.13
electronic article surveillance
EAS
system which detects the presence of transponders, which is often used for anti-theft
purposes
3.3.14
exposure
exposure occurs whenever and wherever a person is subjected to electric, magnetic or
electromagnetic fields or to touch currents other than those originating from physiological
processes in the body and other natural phenomena
3.3.15
exposure level
value of the quantity under analysis when a person is exposed to electromagnetic fields or
touch currents
3.3.16
exposure requirements
standard, recommendation, set of guidelines or limits or other document that defines exposure
levels for guidance, assessment or compliance purposes
3.3.17
far-field
that region of the field of an antenna where the angular field distribution is essentially
independent of the distance from the antenna. In this region (also called the free space
region), the field has a predominantly plane-wave character, i.e. locally uniform distribution of
electric field strength and magnetic field strength in planes transverse to the direction of
propagation
3.3.18
harmonics
multiples of a principal frequency, invariably exhibiting lower amplitudes

– 12 – 62369-1 © IEC:2008
3.3.19
induced current
current induced inside the body as a result of direct exposure to electromagnetic fields
3.3.20
interrogator
module in which all the basic processing of the data protocol takes place and there is an
interface to the transponder (for communicating and facilitating data transfer). An interrogator
is often also known as a reader.
3.3.21
magnetic flux density
B
magnitude of a field vector that is equal to the magnetic field H multiplied by the permeability
(μ) of the medium
B = μH
3.3.22
magnetic field strength
H
magnitude of a field vector in a point that results in a force (F) on a charge (q) moving with
velocity (v)
F = q()Ȟ × μ H
[or magnetic flux density divided by permeability of the medium, see “magnetic flux density”]
3.3.23
near-field
region generally in proximity to an antenna or other radiating structure, in which the electric
and magnetic fields do not have a substantially plane-wave character, but vary considerably
from point to point. The near–field region is further subdivided into two sub-regions. The
reactive near-field region is closest to the radiating structure and contains most or nearly all
of the stored energy. The radiating near-field region is where the radiation field
predominates over the reactive field, but lacks substantial plane-wave character and is
complicated in structure
3.3.24
permeability
μ
property of a material which defines the relationship between magnetic flux density B and
magnetic field strength H. It is commonly used as the combination of the permeability of free
space and the relative permeability for specific dielectric materials
μ = μ μ = B/H
R 0
where
–1
μ is the permeability of the medium expressed in henrys per metre (Hm )
μ is the permeability of a vacuum
μ is the relative permeability
R
3.3.25
permittivity
ε
property of a dielectric material (e.g. biological tissue) which defines the relationship between
electrical flux density D and electrical field strength E. It is commonly used as the combination

62369-1 © IEC:2008 – 13 –
of the permittivity of free space and the relative permittivity (or dielectric constant) for specific
dielectric materials
İ = İ İ = D/E
R 0
where
–1
ε is the permittivity of the medium expressed in farads per metre (Fm )
ε is the permittivity of a vacuum
İ is the relative permittivity
R
3.3.26
power density
S
power per unit area normal to the direction of electromagnetic wave propagation. For plane
waves the power density (S), electric field strength (E) and magnetic field strength (H) are
related by the impedance of free space, i.e. 377 ȍ
E
S = = 377H = EH
–1 –1 –2
where E and H are expressed in units of Vm and Am , respectively, and S in Wm .
NOTE Although many survey instruments indicate power density units, the actual quantities measured are E or H,
or the square of those quantities. It should be further noted that the value of 377 Ω is only valid for free space, far
field measurement conditions (and does not apply for inductive devices operating in the reactive near field).
3.3.27
radio frequency identification
RFID
system which reads the data stored in transponders, using electromagnetic fields. Some
system/transponder combinations also allow new or updated data to be transferred to the
transponders (read/write)
3.3.28
read
decoding, extraction and presentation of data from formatting, control and error management
bits sent from a transponder
3.3.29
read/write transponder
transponders that are capable of having their data repeatedly modified are called read/write
transponders
3.3.30
reference value
reference level
maximum permissible exposure
action value
value of exposure in a measurable quantity that has been conservatively derived from basic
restrictions or basic limits in such a way that compliance with the value ensures that there is
also compliance with the basic restrictions it is derived from. Non-compliance with the
reference value does not imply non-compliance with the basic restrictions it is derived from,
only that additional evaluations or actions are required to show such compliance.

– 14 – 62369-1 © IEC:2008
3.3.31
root-mean-square (rms)
effective value or the value associated with joule heating, of a periodic electromagnetic wave.
The rms value is obtained by taking the square root of the mean of the squared value of a
function
N
X = [f (x)] dx
³
N
Or in its equivalent form for a series of discrete parts
N
X = ()X
n
¦
N
n=1
NOTE Although many survey instruments indicate rms, the actual quantity measured is root-sum-square (rss)
(equivalent field strength). The value rss is obtained from three individual rms field strength values, measured in
three orthogonal directions combined disregarding the phases.
3.3.32
root-sum-square
rss
effective value or the value associated with joule heating, of a periodic electromagnetic wave.
The rss value is obtained by taking the square root of the sum of the squared value of a
function
N
X = [f (x)] dx
³
Or in its equivalent form for a series of discrete parts
N
X = ()X
¦ n
n=1
3.3.33
specific absorption rate
SAR
time derivative of the incremental electromagnetic energy (dW) absorbed by (dissipated in) an
incremental mass (dm) contained in a volume element (dV) of given mass density (ρ )
d dW d § dW ·
§ ·
¨ ¸
SAR = ¨ ¸ =
¨ ¸
dt dm dt ρdV
© ¹
© ¹
–1
SAR is expressed in units of watts per kilogram (Wkg ).
NOTE SAR can be calculated by:
σ E
i
SAR =
ρ
62369-1 © IEC:2008 – 15 –
dT
SAR = c
i 0
dt
at t
where
E : rms value of the electric field strength in the tissue in V/m
i
σ : conductivity of body tissue in S/m
ρ : density of body tissue in kg/m
–1 –1
c : specific heat capacity of body tissue in J kg K
i
dT
: initial time derivative of temperature in body tissue in K/s
dt
3.3.34
touch current
contact current
electric current passing through a human body or when it touches one or more accessible
parts of an installation or of equipment transponder
3.3.35
transponder
transmitter/receiver pair contained within a single package designed to respond to an external
interrogating signal. This is often also referred to as a tag, electronic tag, electronic label,
electronic bar-code, RFID chip, code plate and various other similar terms
3.3.36
wavelength
wavelength (λ) of an electromagnetic wave is related to the frequency (f) and velocity (Ȟ) of
the wave by the expression
Ȟ
Ȝ =
f
–1
where Ȟ is the velocity of the wave in ms
NOTE In free space the wave velocity is the velocity of light in free space, c.
4 Measurements and calculations for equipment evaluation
4.1 Introduction
This clause provides a three-stage method of exposure evaluation. The stages vary in
complexity and the one most suitable for the equipment and the exposure situation should be
used.
Evaluations are made either against basic restrictions or against derived reference values.
Reference value parameters are directly measurable and so are used for the simplest
evaluation method in 4.2. Basic restriction parameters provide a more fundamental evaluation
of exposure but are difficult or impossible to measure directly, so calculation, and numerical
modelling techniques are required. Evaluations against basic restrictions are provided in 4.4
and 4.5, with increasing levels of sophistication and complexity. In 4.4, the modelling takes
account of the non-uniformity of the fields, but not of human tissue. In 4.5, the modelling also
takes account of the non-uniformity of the human tissue and its properties.
Subclause 4.6 contains a method to demonstrate compliance for contact and limb currents.
This shall be used in all cases.

– 16 – 62369-1 © IEC:2008
4.2 Evaluation against reference values
4.2.1 General
This subclause describes the method for determining compliance of a system to field strength
reference values.
The measuring instrumentation must be suitable for purpose and must cover the frequency
range of emissions from the unit under test. In the event that broadband instruments are used
the bandwidth of the instrumentation must cover the range of frequencies emitted. The
measuring instrumentation may have a frequency dependent response that correlates with the
limits. All measurement equipment used for the purposes of this standard shall be calibrated,
with traceable results, via a suitable accredited laboratory. The test site or facility used for
product compliance evaluations shall also be suitably calibrated; however this may not be
possible for measurements made at equipment installation sites. In the case of an un-
calibrated test site or facility, care must be taken to avoid, or take into account, external
influences which could affect the results. All such effects and remedies should be noted in the
evaluation report, together with any uncertainties, which are created from them.
Instrumentation used to measure exposure levels may be commercially available or
specifically designed for purpose. IEC 61786 and IEC 61566 provide information about such
measurements and equipment.
In order to fully characterise the exposure conditions it may be necessary to use several
instruments, including broadband meters, oscilloscope or spectrum analyser. If more than one
instrument is used, some overlap of frequency range of the instrument may not be avoidable
however. In this case, unnecessary overevaluation of the levels should be minimized. Spectral
information is required to determine compliance with frequency dependent levels.
Measurements shall be performed using instrumentation capable of measuring relevant
frequency domain and time domain characteristics of the signal. In the case of time domain
measurements, it may be necessary to determine the frequency content to compare with the
reference values.
It is necessary to consider the frequency range of the emissions and any time varying
modulation. In addition, the duration of the exposure should be noted. These must be
considered where time averaging of exposure is allowed. It may be necessary to calculate the
instantaneous maximum field strength for comparison with limits for pulsed sources. It may
also be necessary to sum the field level at each frequency in accordance with the appropriate
exposure requirements.
It is important to consider the wavelength of the emissions with respect to the position of the
person to determine whether separate electric and magnetic field measurements are
necessary. In the near field, for example, it may only be necessary to measure magnetic
fields.
The measurements shall be carried out to determine the unperturbed field strengths. For
electric field measurements, the presence of the human body can significantly affect the field
and the instrumentation should be mounted on a non-conductive support. It may also be
appropriate to use a fibre-optic coupled remote read-out unit (or similar means of distancing
the body of the operator) for some electric field measurements.
If a power adjustment is available on the unit under test then
...